The conventional disc brakes include a type that uses caliper carrying guide pins and the structure of the disc brake is simplified by connecting these guide pins in a cantilever-like manner to a support, as disclosed in U.S. Pat. No. 3,081,843. Such simplification is made possible with friction pads carried by the support and an operating load on the guide pins reduced by allowing the support to directly receive a braking torque during a braking operation. In such a type of disc brake, an auxiliary guide pin is removably screwed to the support. When the friction pads are to be replaced, the auxiliary guide pin is removed from the support and the caliper is turned round on a main guide pin to facilitate the replacement work. However, with the auxiliary guide pin screwed to the support, when a vehicle on which the brake is mounted is running, the screw might be loosened by the vibration of the vehicle. To prevent such loosening of the screw, the screw must have a sufficiently great bearing surface. However, increase in the bearing surface of the screw calls for a greater diameter of the guide pin and thus eventually causes increase in the overall weight of the brake. In view of such a problem, it has been impossible to make the bearing surface of the screw sufficiently greater.